1. Field of the Invention
The present invention relates to a lens barrel, more specifically relates to a lens barrel incorporating at least one rotatable optical element that produces a specific photographic effect when rotated on a photographing optical axis.
2. Description of the Related Art
In a lens barrel which incorporates an optical element (e.g., an optical filter or a wide-converter lens) that produces a predetermined photographic effect when inserted into an optical path on a photographing optical axis, it is necessary to remove such an optical element from a position on the photographing optical axis when the optical element is not used. Among such kind of optical elements, in a particular type of optical element which functions when driven to rotate such as a polarizing filter, the optical element needs to be driven not only to be inserted into and removed from an optical path on the photographing optical axis but also to rotate in an inserted state of the optical element, which may complicate the drive mechanism for the optical element.